Reversing mechanisms of this type in which the main direction of travel is changed from forward to backward with the help of a rudder unit, for example by pivoting or swiveling a steerable propeller, are known. They generally also operate satisfactorily. In spite of this, improvements are useful in particular for the personnel which is accustomed only to normal rudder units wherein a reversing of the main direction of travel is not possible. For the reversal from forward to backward and vice versa, it is necessary, for example in the known steerable propellers for the underwater part to be swung at 180.degree. from the steering control. If the steering control is for example a hand wheel, when this must be rotated 3 to 20 times to one direction depending on the translation between the handwheel and the steerable propeller in order to achieve the desired thrust reversal. Particularly during maneuvering in narrow waters in which the ship must be shifted only for a few meters or centimeters, the steerable propeller is superior to other drive and control units, however, it requires also a certain expense in force and attention. In addition, difficulties can result during the adjustment of the steering control and rudder indication. If reversing of the main direction of travel is not done with the necessary speed, it is possible when dealing with inexperienced operators that an unintended lateral thrust, a so-called "deterioration in the direction of travel" will result.
Therefore the basic purpose of the invention is to simplify and make safe the operation of the control for steerable propellers, jet rudders or similarly acting drive mechanisms of ships.
The invention is based substantially on separating the control of the direction of travel (right, left) from the choosing of the main direction of travel (forward, backward).
The steerable propeller of the jet rudder or the other thrust producer can therewith be reversed directly at 180.degree. from the control console with a selector switch for the main direction of travel (forward, backward) being indepenent from the remaining control.
A particularly advantageous and simple reversing mechanism results from the drive mechanism for the pivoting of the thrust producer, for example steerable propeller, for the right-left travel being combined with the drive mechanism for the reversal of the main travelling direction (forward, backward).
In order that it is also possible to change with the selector switch device for the main travelling direction also the direction of rotation between the steering control and the rudder movement and/or direction of travel indicator, the reversing mechanism is inventively further developed with the selector switch device containing a switching mechanism for the main travelling direction, with which switching mechanism the desired-actual value comparison device for forward travel which is associated with the steering control (left, right) is switched over to a different desired-actual value comparison device for backward travel or vice versa.
In order to prevent the thrust producer from producing during reversal of the direction of travel a damaging lateral thrust, the invention can be developed wherein the drive mechanism for the pivoting movement for reversing the main direction of travel (forward, backward) is designed for an accelerated pivoting movement (quick reversal), for example by a suitable valving arrangement. In order to ensure a quick reversal of the direction of travel, there exists always the necessary power reserve without having to construct the respective drive machine correspondingly large.
The invention also assures a safe operation of the entire machine installation during the reversal operation without causing the attention of the operators to be diverted from the surroundings.
Of a particular importance is the invention for ships or the like having several thrust producers, thus for example for double units with steerable propellers. Both steerable propellers are controlled synchronously from a steering control. If a reversal takes place with a selector switch for the main direction of travel, then a switching arrangement can be used which, during the change of the main direction of travel, gives directions of rotations which are opposite for both steerable propellers. This assures that also in the case of a not quite taken back speed of the drive machine the ship does not "falter" from the desired direction of travel.
The invention permits a reversal of the steerable propeller quickly and without any effort to 180.degree. and to thus change the main direction of travel. A selector switch for the main direction of travel is provided for this purpose in the control console. If the main direction of travel is changed through this selector switch, then the steerable propeller rotates 180.degree. independent from the remaining rudder position control and therewith reverses the thrust direction. During reversal, it is possible for the selector switch to connect for a short time a high control power to the normal one, so that a high control speed is achieved and the desired change in the direction of travel is carried out as quickly as possible. The speed and the clutch of the drive machine can now be coupled with the selector switch for the main direction of travel. During a changing of the desired direction of travel, the speed is then automatically taken back and if desired the propeller is uncoupled. The ship remains then in its desired direction of travel without causing any significant lateral thrust to occur which would be damaging. In addition, a reversal of the direction of rotation between the controlled rudder position, steerable propeller and direction of travel indication can be switched with the selector switch, thus it is possible to achieve in every main direction of travel forward or backward a clear association between the controlled rudder position, direction of travel of the ship and direction of travel indication. Since a reversal of the direction of rotation between lead and steerable propeller equals a reversing of the polarity of the desired-actual value comparison, it is now possible to use for the control simple potentiometers and bridge balance circuits. Different potentiometers are used for the forward travel and for the backward travel, of which only one section of 180.degree. each is needed. The selector switch for forward backward travel thus does not only reverse polarity of the direction of rotation, but switches over at the same time to the potentiometer which is necessary for the desired direction of travel.
Further advantages are created by the invention. Thus it is for example possible to choose the direction of rotation for the reversal which is released by the direction of travel selector switch, so that it coincides with the direction of rotation of the vertical shaft for the drive of the steerable propeller. From this, smaller control forces are created and the control elements are protected.
Further advantages and characteristics can be taken from the following description.